Thermoelectric generator including a vibratory burner



L. HUBER Feb. 24, 1970 THERMOELEC'I'RIC GENERATOR INCLUDING A VIBRATORY BURNER Filed Sept. 17, 1965 .5 Sheets-Sheet 1 INVENTOR. zooms Fudge Arron/vans:

L. HUBER Feb. 24, 1970 THERMOELECTRIC GENERATOR INCLUDING A VIBRATORY BURNER Filed Sept. 17, 1965 3 Sheets-Sheet 2 UUUHUUUU :UUUUUU UUUUUUU 1 N VEN TOR. LUD W16 HUBER Feb. 24, 1970 L. HUBER 3,497,397

THERMOELECTRIC GENERATOR INCLUDING A VIBRA'I'ORY BURNER Filed Sept. 1'7, 1965 3 Sheets-Sheet 5 Q Q g a 9 Q Q Q 9 E2 LL. Ll. Q Q Q i l3 Ll g; P Q \T J q E If \Q 1 I I R I i f lubwl il zl f k United States Patent 3,497,397 THERMOELECTRIC GENERATOR INCLUDING A VIBRATORY BURNER Ludwig Huber, 1S Saarlandstrasse, 7000 Stuttgart- Mohringen, Germany Filed Sept. 17, 1965, Ser. No. 488.101 Claims priority, application Germany, Oct. 14, 1964,

5 .026 Int. Cl. l-l0lv ]/3() US. Cl. 136-208 13 Claims ABSTRACT OF THE DISCLOSURE A thermoelectric generator includes a housing having an interior inwardly spaced inner wall of a ceramic material forming a cylindrical ceramic shell. A vibratory burner is arranged within the shell and it includes a transversely extending combustion chamber adjacent one end and a coiled vibratory tube which is wound around a centrally positioned exhaust mufiler having a discharge extending through one end of the housing. The tube is arranged to discharge into a turbine which is rotatably mounted adjacent one end of the mufiier and which drives a fan for directing cooling air into the housing and between the ceramic shell and the exterior of the housing. A plurality of thermocouples are arranged to extend through the ceramic shell and include hot terminal plates lining the interior of the shell which are exposed for radiant heat transfer from the vibratory burner. All of the thermocouple hot plates are spaced outwardly from the vibratory burner tube. The cold terminals are exposed on the outside of the ceramic shell at a location to receive a cooling from the cooling air passed thereover.

This invention relates in general to the construction of thermoelectric generators and, in particular, to a new and useful thermoelectric generator and heater combination employing a vibratory or resonant burner as heating means.

The present invention particularly relates to the construction of a thermoelectric generator which is advantageously made to include means for providing heating of air or a similar fluid for space heating or other requirements. A particular feature of the invention is that the thermoelectric generator is constructed with thermocouples arranged exteriorly and out of contact with a central heating device such as a resonant burner heater. The invention employs a heat generator or heater which has no electric current requirements during operation and the energy produced by such heater is used to drive cooling air for maintaining the cooling air flow over the cold joints of the thermocouples. The hot joints of the thermocouples, which are preferably formed by semiconductors, are arranged in an area which encloses without contact at least a portion of a so-called vibratory or resonant burner which provides a heating source. The thermocouples are arranged so that the hot joints are exposed to the heat radiation produced by the vibratory burner. The vibratory burner comprises a combustion chamber having a vibration tube and which operates because of its mechanical or accoustical natural frequencies to draw in fuel and air and to efiect detonation and combustion and the discharge of exhaust gases with high energy. During this process, the combustion chamber and the vibration tube are useful because of the to and fro oscillation of the gas masses during the intake and combustion process. The combustion gases generated will exit from the burner with a high kinetic energy which may be utilized in accordance with the present invention such as for producing a vacuum and inducting fiuid flow when employed in an ejector.

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In a preferred arrangement of the invention, the thermocouples are arranged to extend through a wall of insulating material, such as a ceramic shell. The combustion gases are generated within a combustion chamber located within the ceramic shell so that the ceramic shell itself need not be made air-tight. The ceramic shell is preferably in a cylindrical shape and surrounds a similarly shaped sound damper or muffler device which is arranged at a spaced location within the ceramic cylinder and receives gases which are discharged by the vibratory burner and a gas turbine driven by these gases. The thermocouple legs are advantageously connected externally and internally of the ceramic shell by means of spaced plates, with gaps being left between the plates for mutual insulation of the thermocouple joints. The plates serve at the same time for heat exchange, that is, the internal ones provide an absorption of heat by direct heat radiation from the vibratory burner and by heat conduction by gas circulated on the interior of the shed between the plates and the mufller for the gases. Externally, the plates are washed by a cooling air flow produced by a fan operated by the gas turbine to maintain the cold joints of the thermocouples at a lower temperature.

A feature of the construction is that the vibratory burner is mounted to extend through the ceramic shell and to discharge through a vibratory tube which extends around a concentrically arranged cylindrical mufiler. Before entering the mufller, the gases are advantageously directed to a gas turbine where some of the kinetic energy thereof is utilized in driving a fan for the circulation of cooling air around the exterior of the ceramic shell and heat exchange relation with the thermocoupled plates at the cold joints. The construction is such that neither the thermocouple joints nor the thermocouple legs themselves come into contact with the combustion gases. Generally, a positive pressure will prevail in a space defined by an outer casing and the exterior of the ceramic shell which is produced by the blower which is driven by the turbine operated by the gases from the vibratory burner. This air, which is initially heated by flow over the thermocouples, may also be directed, after flow over the thermocouple plates, into heat exchange relationship with a continuation of a discharge pipe for the combustion gases and around a secondary sound damper or mufller device. The thus heated air is available for heating oils, fluids or space heating, as desired.

A further feature of the invention is that the exhaust gases which are still at relatively high kinetic energy after they leave the mull ler may be employed for inducing the flow of other fluids, such as for removing gases from the thermoelectric generator itself or for evacuating the cool air from a space which is being heated by the air produced by the heater, for example.

Accordingly, it is an object of the invention to provide a thermoelectric generator in which thermocouples are maintained in a cylindrical shell with the hot joints located on the interior surface and subjected to heating by an independent heater device and with the cold joints adapted to be located exteriorly of the shell.

A further object of the invention is to provide a thermoelectric generator in which the hot joints of the thermocouples are maintained in heat exchange relationship with a heater and which operates without any current supply.

A further object of the invention is to provide a heater construction which includes thermoelectric generators having thermocouples exposed at the hot joint side to heat from a separate heater element and which are interconected electrically so that the electricity generated by the thermocouples is available for separate use.

A further object of the invention is to provide thermoelectric generator and heater constructions which are simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. 1 is a partial axial sectional view of a heater having a thermoelectric generator constructed in accordance with the invention;

FIG. 2 is a section taken on the line 22 of FIG. 1;

FIG. 3 is a somewhat schematic development of the interior of the thermocouple generator;

FIG. 4 is a partial axial sectional view of an after portion of another embodiment of heater; and

FIGS. 5 and 6 are partial plan views of thermocouple ring constructions showing various embodiments for accommodating the thermocoupled elements.

Referring to the drawings in particular, the invention embodied therein comprises a heating device generally designated 60 which may advantageously be, for example, a space heater for an automobile. In accordance with the invention, the heating device 60 includes a combustion device generally designated 62 for independently generating high temperature gases which is located within and provides heating for the hot joints of a thermoelectric generator generally designated 64'.

The combustion device 62 includes a tubular element defining a combustion chamber 1 having an intake for combustion air 66 which is effective during operation of the device to draw in air through a check valve 2. Fuel is admitted through a conduit 68 and a carburetor 3 to the lower portion of the combustion chamber 1. A coiled resonant or vibration tube 4 is connected to the combustion chamber 1 and it is provided with an end 5 which discharges into the outer periphery of a radially admitted turbine 6. In those cases where special importance is attached to a uniform temperature gradient over the entire length of the combustion device 62, the resonant coil 4 is wound with a decreasing pitch toward the end 5 as shown in FIG. 1. The blades 7 of the radial turbine 6 are so arranged that the flow through the turbine is from the outer periphery toward the axis and into a sound damper or cylindrical mulfier 8. The exhaust gases are discharged from the muffler 8 through an exhaust conduit or tube 9.

The combustion device 62 is enclosed within a ceramic shell 10 which is traversed by a plurality of thermocouples 11, each of which includes positive and negative legs. The ends of the ceramic :shell are closed by end walls 12 and 13, respectively. A feature of the invention is that the thermocouples are embedded in the ceramic shell and the hot joints extend through the interior of the shells and are fastened to inner plates 15. The plates 15 will be subjected to heating by the combustion device 62. The outer cold joints of the thermocouples 11 are connected to exterior plates which carry cooling vanes 17. The inner plates and outer plates are connected electrically to connect all the thermocouples in series. The electrical conduits 18 and 19 indicated at one end of the device are connected through a block and through a casing or tube 25 to terminals 20 and 21, respectively, for use of the current produced as desired.

As indicated in the drawings, the casing is substantially cylindrical and is spaced from the outer walls of the shell 10 sufiiciently to accommodate the cooling vanes 17. The casing includes an intermediate portion 25a and end portion 25b formed as a cylinder of lesser dimension than the major portion 25. The front or forward end of the tube 25 is closed by a screen or trellis 23. The turbine 6 includes a bearing block portion which rotatably supports a haft fo a ventilator wheel or fan 2.2 which is driven by the rotating turbine. Rotation of the fan 22 causes air to be drawn in through the trellis 23 and to be forced around the end wall 13 and into the chamber 24 between the ceramic shell 10 and the casing 25. This incoming air sweeps past the cooling vanes 17 and maintains the cold thermocouple joints at a relatively low temperature. The action of the fan or blower 22 is sufficient to produce a positive pressure in the chamber 24. If there is any leakage in the combustion device 62, then the air will flow from the exterior of the device toward the center and it is not normally necessary to reduce the pressure within the shell 10 and exterior of the muffler 8. In some instances, however, it is desirable to interconnect a tube 26 from the interior space within the shell 10 to the intake hood 28 at its opposite end to withdraw gases from chamber 70. Due to the action of the combustion device 62 and to the drawing in of the air through the valve 2, the pressure within the intake hood 28 is maintained below atmospheric pressure. An extension conduit 29 is connected into the tube 26 from the bearing block 30 in order to withdraw any impurities which may be in the block during the operation. In some instances it is preferable to terminate the tube 26 in the outside air rather than in the hood 28. When connected as indicated in FIG. 1, however. the additional air which is drawn into the intake hood 28 is regulated by a rotatable cover portion 27 having an opening 2811 which may align with an opening 280 when the cover 27 is rotated to an aligned position or it may be oriented for any partial admission of air through the bores 28b and 280. An inner cover 28a closes the interior of the hood from the space within the casing 25 surrounding the shell 10.

It can be readily seen that the shell 10 need not be airtight. It suffices that it may comprise an electrically nonconducting and heat-insulating and heat resisting material. If the combustion device, including combustion chamber 1, should develop any leaks, the exhaust gases will still not get into air which is to be used for space heating, for example. Any exhaust gases which leak from the combustion chamber 1 will be directed through the tube 26 into the hood 28. If there is a major leakage of exhaust gases, the flow of the exhaust gases through the tube 26 into the hood 28 will cause the vibratory burner to stop functioning since the ratio between the air and fuel will be disturbed by any admixture of the exhaust gases to a great extent. Inside of the cylinder 10, a temperature of about 1000 C. may occur due to radiation equilibrium and heat conduction. Both the combustion chamber 1, the tube 4 and the mufller 8 all act to radiate beat out wardly to the plates 15 which receive such heat therefrom.

The cooling ribs 17 are advantageously made of an excellent heat conducting material such as aluminum or copper. In some instances, the plates 15 are also provided with internally extending heat-exchanging ribs.

Parts are provided (not shown) for operating the vibratory burner or combustion device 62 for effecting the starting, the supply of air and the supply of fuel in a satisfactory manner and for effecting the ignition of the fuel and air mixture. Such parts are arranged in the cooling zone 24 and are located on plate 280 although they are not indicated in the drawing. Because the exhaust gases cannot come into contact with the thermocouples 11, corrosion and chemical changes cannot take place. In addition, the surfaces of the elements and the plates cannot become fouled.

As indicated in FIG. 3, the inner plates 15 are disposed around the aperture 40 for the combustion chamber 1 of the combustion device 62. The current leads l8 and 19 are connected to the plates to connect the thermocouple elements in series.

As indicated in FIG. 4, the trailing end of the heater 60 may be made to include the end section 42 connected over the end of a casing or tube 25 and which terminates in an opening 46 for the discharge of heated air such as for space heating purposes, In the embodiment of FIG. 4,

a discharge tube 9 similar or identical to the exhaust tube 9 is connected through a wall 12 of a heater and into a secondary sound damping device or muffier 41. The air is directed out of the mufiler 41 through an opening 44 and into a coil 45 which is directed out through an opening in the hood 42 and terminates in a nozzle 47. Air which circulates bewteen a thermocouple shell and a casing is then directed over cooling ribs 43 which extend around the heating coil 45 and additional heat is imparted to the air from the muffler 41, the coil 45 and the ribs 43. The air which is delivered out through the opening 46 is thus available for any purpose. It should be appreciated that the air discharged through the opening 46 may be used to heat air such as in a space heater or may be used for heating oil or other fluid media, if desired.

The residual kinetic energy still present in the gases generated by the combustion device 62 in the embodiment of FIG. 1 and delivered through an exhaust tube of the type indicated 9' in FIG. 4 may be employed by directing it out of the nozzle 47 in an ejector device 70, which is connected to a conduit 48 for producing a negative pressure and fluid flow in the conduit. The conduit 48 may be connected, for example, to the interior of the casing 25 for the purpose of evacuating air or gases therefrom or to the bearing block 30 for evacuating air and other undesirable contaminants from this location. In a preferred arrangement, the conduit 48 may be connected to the tube 26 for providing a negative pressure on this tube.

In the inventive thermo generator device, it should be realized that the entire current energy generated by the thermocouples is available for free use. The construction of the device is very inexpensive because it pro vides a very excellent spatial arrangement and uniform heat load may be produced by the vibratory combustion device 62. In addition, the cooling current for the cold side of the thermocouples is produced without recourse to a supply of current by an electrically driven fan. Instead air is directed by the fan 22 which is driven by gases generated by the combustion device. The device is such that it is not necessary to provide a thermocouple which must furnish current for the drive of the heating system or for a cooling fan, since this is accomplished by the combustion device itself. Therefore, the useful output of the thermoelectric generator is substantially increased. A feature of the preferred embodiment of the thermoelectric generator is that the combustion de vice may be employed for heating the air for heating purposes such as for space heating.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

In FIG. 5 there is indicated a means for the construction of the ceramic cylinder 10. In the embodiment of FIG. 5, the cylinder is made up of two rings 50 and 51 having cylindrical cavities 52 defined in their surfaces which provide means for drawing the thermocouples therethrough.

As indicated in FIG. 6, rings 53 and 54 may be provided which include shallow depressions 55 into which thermocouples 111 may be inserted. In this embodiment, the thermocouples are made as flat as discs or rod elements. The rings, of course, may be slotted and instead of rings, semi-cylinders may be employed.

What is claimed is:

1. A combination thermoelectric generator and heating device comprising means defining a combustion chamber for a vibratory burner, fuel and air inlet means connected to said combustion chamber, a vibratory tube connected to said combustion chamber and including a coil portion and an end discharge, a turbine rotatably mounted adjacent the end discharge of said vibratory tube for receiving gaseous products of combustion generated in said combustion chamber to effect rotation of said turbine, a fan connected to said turbine and rotated thereby, a shell defining a closed chamber surrounding at least said vibratory tube an dhaving a plurality of thermocouples extending therethrough with the legs joined to a hot end extending through said shell and exposed on the interior thereof and jointed to a cold end and extending through the exterior of said shell and exposed thereon, a casing surrounding said shell, said casing forming an enclosure for said fan with an inlet opening for drawing air in to said fan and circulating it around said shell and between said casing and said shell for cooling said cold joints.

2. A combination heater and thermoelectric generator according to claim 1, including a fluid flow conduit, said coil portion of said vibratory tube having an end extending out of said casing and terminating in a nozzle within said fluid flow conduit for producing a negative pressure therein for inducing the flow of fluid therethrough.

3. A combination thermoelectric generator and heater according to claim 1, including a muffler disposed within said shell and arranged to receive gaseous discharge by said turbine, an exhaust tube extending from said muffler to a second mufller, and a coil tube extending from and around said mufiler and located within said casing and interiorly of said shell, said air which is circulated by said fan passing over the exterior of said shell and over the coiled tube extending around said muffler.

4. A combination thermoelectric generator and heater according to claim 3, wherein said casing terminates in an opening adjacent said second mutfler for the discharge of heated air for uses such as for space heating.

5. A thermoelectric generator and heater according to claim 1, wherein each of said thermocouple elements includes a cold joint connected to a cooling plate, said plates being arranged in spaced relationship on the exterior of said shell.

6. A combination thermoelectric generator and heater according to claim 5, including means for connecting of said thermocouple elements together in series and for connecting said connected plates to separate terminals at the exterior of said casing.

7. A thermoelectric generator comprising a vibratory burner having a combustion chamber and a vibratory tube, a closed chamber surrounding said vibratory tube and carrying a plurality of plates at the interior arranged in spaced relation to said tube, a thermocouple associated with each of said plates and being connected at its hot joint terminal to said plates, said thermocouples having their cold terminals exposed on the exterior of said closed chamber, said thermocouples forming the thermoelectric generator.

8. A thermoelectric generator according to claim 7, including a sound damper located within said closed chamber and being connected to said vibratory tube, said vibratory tube including a spiral portion encircling said sound damper.

9. A thermoelectric generator, comprising combustion means for producing high temperature gaseous products of combustion including a vibratory burner, a plurality of thermocouples arranged adjacent said combustion means, each of said thermocouples including a hot terminal exposed for radiant heat transfer and spaced from said combustion means and a cold terminal disposed away from said combustion means, a burner enclosing cylindrical shell carrying said thermocouples with the hot terminals extending inwardly therefrom and with the cold terminals exposed on the exterior thereof, a turbine fan connected to said combustion means, and easing means providing for the flow of air around the exterior of said shell by action of said turbine fan to maintain the cold joints of said thermocouples at a lower 7 temperature than the hot points in the interor of said shell.

10. A thermoelectric generator according to claim 9, wherein said vibratory burner includes an exhaust conduit terminating in a nozzle, and ejector means including said nozzle and a surrounding conduit for producing a fluid How in said surrounding conduit.

11. A thermoelectric generator according to claim 9, including fan means connected for operation by said gaseous products of combustion generated by said combustion means for maintaining the space between said casing and said shell at a higher pressure than the space between said shell and said combustion means.

12. A thermoelectric generator according to claim 11, including a burner suction, and. wherein the space between said shell and said combustion means is connected to the suction of said vibratory burner.

13. A thermoelectric generator comprising combustion means for producing high temperature gaseous products of. combustion including a vibratory burner, a plurality of thermocouples arranged adjacent said combustion means, each of said thermocouples including a hot terminal exposed for radiant heat transfer and spaced from said combustion means and a cold terminal disposed away from said combustion means, and a burner-enclosing cylindrical shell carrying said thermocouples with References Cited UNITED STATES PATENTS 1,118,269 11/1914 Creveling 136208 X 2,133,349 10/1938 Gray 165135 X 2,390,578 12/1945 Findley 136-209 3,150,656 9/1964 Huber 136-205 X 3,297,492 1/1967 Pepper 136208 FOREIGN PATENTS 666,519 2/1952 Great Britain.

WINSTON A. DOUGLAS, Primary Examiner M. J. ANDREWS, Assistant Examiner US. Cl. X.R. 

